The invention concerns an electric motor, in particular an external rotor motor, comprising a stator bushing in which components that generate heat are disposed and comprising a rotor housing that has at least one air conveying element.
Electric motors are known in which the stator bushing on the exterior near the rotor housing has cooling elements in the form of cooling ribs that are uniformly distributed at a spacing about the circumference of the stator bushing. Opposite these cooling ribs there are rotor cooling ribs that form an air conveying element. Upon operation of the electric motor, as a result of the cooling ribs rotating relative to one another, external air is sucked in as cooling air and guided between the cooling ribs that rotate relative to each other. A good air guiding action along the cooling ribs is not possible in this way. Moreover, because of the edges facing each other of the stator cooling ribs and the rotor cooling ribs, a significant noise development occurs that is disruptive when using the electric motor.
Electric motors are also known in which the rotor on the inner side has a cooling wheel. With it, external air is sucked in through openings in the motor housing. The air flows past the motor electronics to be cooled and absorbs heat by doing so. The heated air then exits laterally from the motor housing.
In another known electric motor the rotor is provided with a fan wheel for cooling control electronics disposed within a housing provided with cooling ribs.
The invention has the object to design an electric motor of the aforementioned kind in such a way that it ensures an optimal cooling action with minimal noise development while it has a simple configuration.